HELP - I've made a mistake

I finished knitting and have half assembled the Kenmare design from the Softknits Collection. I was about to sew front to back when I noticed that I left out the 2 1/2 " of stockinette stitch that preceeds the main portion of the pattern. This leaves the front 2 1/2" short, so if I can rip out from the bottom I could add the necessary portion. Can I do this ????